Navy Uses Railgun To Launch Fighter Jet [in 2015]

Slashdot ^ | 12/22/10 | samzenpus

[Clint Williams]

Phoghat writes

"In 2015 the aircraft carrier USS Gerald R. Ford will take to the seas and the plan is to use a railgun to launch planes, instead of steam powered catapults. From the article: 'The Navy developed its Electromagnetic Aircraft Launch System as a replacement for the steam catapults currently used on aircraft carriers. The EMALS is a linear induction motor that's capable of accelerating a 100,000 pound aircraft to 240 miles per hour in the space of 300 feet. Compared to a steam catapult, the railgun catapult is much smaller, more efficient, simpler to maintain, gentler on airframes, and can deliver up to 30% more power. It's also capable of being cranked down a whole bunch, meaning that it can also launch smaller (and more fragile) unmanned drones.'"

[fightinbluhen51]

Well...that’s nice...but that person is mixing stories.

The navy is testing a rail gun (true) but they are also testing an electromagnetic launching system that is similar to roller coaster launchers.

[muddler]

Can a human survive that?

[Hodar]

US Gerald Ford - what an unfortunate name. Named after a Zero-term president, who pardoned Pres. Nixon.

Will probably hit a sandbar, and tip over and sink.

But, on the serious side - there are two components to launching and landing aircraft. Won’t the railgun launcher require MORE energy than conventional launching? Won’t the RF ‘noise’ of the rail create such a ‘loud’ EMF wave - that it will basically create havok with onboard electronics, as well as aircraft computers, radar and eavesdropping efforts?

If you can get an aircraft from 0 to take-off speed using a railgun (and not killing the pilot or destroying the plane) - this means you need a shorter runway. Now you have a really short runway - how do you intend to reclaim these aircraft on the smaller runway?

[TalonDJ]

Won’t the railgun launcher require MORE energy than conventional launching? Won’t the RF ‘noise’ of the rail create such a ‘loud’ EMF wave - that it will basically create havok with onboard electronics, as well as aircraft computers, radar and eavesdropping efforts?

No, and No.

[SampleMan]

Naming ships after recent (and 30 years is recent) Presidents is a bad idea. And after naming ships after Carter, Ford, and G.H.Bush, we have set the bar so low that every POTUS will qualify. Frankly, I don't think anything built or paid for by the government should ever be named after a living Congressman, President, etc. Its bad form in a free republic to do such things.

The Navy has given up all tradition in ship naming and now just treats it like a charitable naming opportunity. No doubt there is a list of political names to going whoring to Congress with. Had the Dems retained power for another 10 years, we may have been treated to a USS Malcolm X, USS Acorn, USS Socialized Medicine, etc.

We should give up on procuring ships until we have been able to procure a set of testicles for the Admiralty.

[SampleMan]

If you can get an aircraft from 0 to take-off speed using a railgun (and not killing the pilot or destroying the plane) - this means you need a shorter runway. Now you have a really short runway - how do you intend to reclaim these aircraft on the smaller runway?

The stroke likely won't change. Its already as progressively loaded as the aircraft will handle. And aircraft are never recovered using more than 1/3 of the carrier (the angle). What changes is the need to produce vast quantities of steam from sea water. Maintenance and below deck space should both be reduced.

[Flatus I. Maximus]

Why not go the rest of the way and sell the naming rights to corporations?

[baddog 219]

The Barrack Obama carrier will be small, pink, and sink itself when confronted.

[SERKIT]

You mean USS Barack Hussein “Titanic” Obama will be a bad name for a Navy ship?

[Never on my watch]

I hope we are done making carriers before the ‘Clinton’, ‘Carter’, or ‘Obama’ hit the seas.

[Hodar]

This graph is for shooting a small projectile - not an aircraft. The amount of current (granted, low voltage) required to move a 14 ton F-15 from 0 to 125+ mph in a short distance has to be stupendous. Now, when you deal with low voltage and high current, Ohm's law eats your lunch.

Voltage = Current x Resistance
Then figure the power dissipation of:
Power = (Current)^2 x Resistance.

Now, in a lab you can get an armature to run in the low milli-ohm range for a few runs. But, exposed to weather, oil, exhaust, ocean spray and other contaminates - the armature will be 'dirty' and easily have more than a few ohms of resistance.

Now, we are going to have a rail system and armature that are going to get white hot in a matter of milliseconds.

And, here's the fun part. Iron is no longer magnetic once it reaches the Curie temperature (~1050 K or ~1,400 F).

Sorry, as an Engineer - I question the feasibility of doing this, both from the power efficiency point of view, as well as the safety, technical capabilty and reliabilty point of view.

[biff]

Yep, as long as the computers are working correctly.

[starlifter]

Wow. You would think the Navy would have considered all of this. What a bunch of dolts!

[edcoil]

Nice idea, sounds like it will work.

[Waverunner]

But no one will be able to find it’s commissioning papers.

[Waverunner]

Don’t ypu know that Obama has secured an infinite supply of Unobtainium from the Russians as part of the START treaty.
This will solve all technical problems, everywhere.

[justlurking]

An linear induction motor is not a railgun.

http://en.wikipedia.org/wiki/Linear_motor

http://en.wikipedia.org/wiki/Railgun

[justlurking]

Can a human survive that?

The electromagnetic launching system (which uses a linear induction motor, not a "railgun") actually reduces the stresses on the airplane and the pilot.

A steam catapult doesn't apply a constant acceleration force for the entire duration of the launch. It's very difficult to regulate the steam expansion over the length of the launcher.

On the other hand, the electromagnetic launcher can be controlled simply by regulating the current applied. So, a constant force can be applied for the entire launch, and accelerate the airplane/pilot much more smoothly.

The electromagnetic system can also be "dialed back" to launch smaller aircraft, like unmanned drones.

[battousai]

The KNS Obama :)